SST SST-ESR2-CLX-RLL ControlLogix Communication Module

The SST SST-ESR2-CLX-RLL is an in‑chassis ControlLogix communications module that bridges Rockwell 1756 ControlLogix CPUs to Modbus networks with 1x Ethernet (Modbus TCP) and 2x serial Modbus channels in a single slot. It supports local and remote ControlLogix racks and, per installation guidelines, up to eight SST modules can be used in one ControlLogix rack. The unit provides galvanic isolation on its serial interfaces (RS232/RS485/RS422) up to 500 V and runs at baud rates from 110 bps to 115.2 kbps, using a shielded RJ45 Ethernet port and a shielded DB9 cable for serial connectivity. It includes 128 MB of onboard shared memory and 8 MB of flash memory for user configuration and firmware, plus a USB port for local configuration boot and firmware upgrades. Diagnostic visibility is aided by a 4‑character display and LEDs indicating Rx, Tx, Link, and 10/100 status. A core feature is Remote Link Library (RLL), which enables remote configuration and diagnostics of the Modbus network through Rockwell RSLinx, eliminating ladder‑logic development for Modbus data transfer. This module is well suited for bridging Modbus devices to a ControlLogix system, supporting supervisory/SCADA tasks, plant monitoring, and integration of Modbus infrastructure into Rockwell‑driven networks with streamlined engineering workflows.